U.S. Pat. No. 4,671,334 (Yadegar et. al.), issued on Jun. 9, 1987, discloses a vehicle sunshade, which is foldable and collapsible for storage e.g. in the glove compartment. The known sunshade is made of plastic, fiberboard, cardboard or the like, without any hollow spaces.
U.S. Pat. No. 4,878,708 (Champane), issued on Nov. 7, 1989, discloses a vehicle sunshield that is made of resilient corrugated cardboard and constructed for use inside the vehicle next to the windshield. The shield is also foldable.
U.S. Pat. No. 4,784,215 (Sing), issued on Nov. 15, 1988, discloses air inflatable insulating shades mountable inside a passenger car compartment to cover the ceiling and both front and rear window. A separate blower is required to inflate the shades.
There is a need for a windshield cover that will keep snow and ice off the windshield without freezing to the windshield. Thus the protection must be mechanical and thermal. Conventional devices are not very efficient for both purposes simultaneously.
It is also known to use protection films which are stretched over the windshield and are secured in the door frame. Such thin, soft films are cumbersome to handle, since it is difficult to attach the films to the windshield. Besides, there is a tendency of these films to freeze onto the windshield.